1. Field of the Invention
The invention concerns a method to detect a specific bacterium in a hollow organ of the human or animal gastrointestinal tract, and an endoscopy capsule to detect such a bacterium and its use.
2. Description of the Prior Art
A frequent cause for complaints of the upper gastrointestinal tract is a bacterial attack of its organs. For example, an attack by Helicobacter pylori has been held responsible for a large range of stomach illnesses that are accompanied by an intensified secretion of stomach acid. Type B gastritis, approximately 75% of gastric ulcers and nearly all duodenal ulcers fall into this category, for example. The examination of the hollow organs of the gastrointestinal tract for colonization by bacteria—in particular for colonization with Helicobacter pylori—is therefore an important component of the diagnosis of stomach illnesses. d by
For example, Helicobacter pylori is detected a breath test in which urea marked with C-13 is administered to the patient. The C-13-marked CO2 that arises upon splitting urea into ammonia and CO2 is detected in the exhaled air. Other methods to detect Helicobacter pylori are based on typical blood values of, for example pepsinogen or gastrin. However, such methods are complicated and less reliable.
An additional possibility to examine the stomach for a colonization with Helicobacter pylori is known as gastroscopy (“stomach endoscopy”). During such an examination the gastroenterologist takes a biopsy of the stomach mucosa in order to examine this sample at a later point in time for an infection with Helicobacter pylori. A known examination method for the tissue sample (biopsy specimen) is the Helicobacter urease test (HU test, abbreviated as HUT), for example. The biopsy specimen is placed in a testing medium (measurement solution) that contains a culture medium for this bacterium that consists of urea and an indicator (litmus). If the Helicobacter pylori bacterium is contained in the sample, the bacterium splits the urea (CO(NH2)2) via urease into ammonia (NH3) and carbon dioxide (CO2). The ammonia then colors the indicator red. The test result is detectable after a few minutes. The initial color change from yellow to red, however, cannot be clearly established under disadvantageous conditions.
Gastroscopy has a low patient acceptance and is unsuitable for conducting screening examinations.
One alternative to the above-described examination of the upper gastrointestinal tract that is implemented endoscopically (stomach endoscopy) is the use of an endoscopy capsule, which is also called an endocapsule or capsule endoscope and is known from DE 101 42 253 C1 and the corresponding US 2003/0060702 A1, for example. Such an endocapsule is a capsule that can be swallowed, the capsule communicating wirelessly with a transmission station outside of the patient's body. The endocapsule moreover, can be navigable in a magnetic gradient field. Such a capsule can be outfitted with sensors that allow it to measure or detect temperature, electrical conductivity, pH value or chemical substances inside a hollow organ, for example. Such an endocapsule can likewise be suitable for targeted administration of medicine.
A method is described in WO 2004/039233 A2. in which the pH value is determined via an in vivo measurement. Ammonium (NH4+) is detected in the stomach via this pH measurement, whereby a conclusion of the presence of Helicobacter pylori should be possible. However, this test for Helicobacter pylori is not reliable since an acid medium (pH value between 1.5 and 2) does not necessarily have to be present in the stomach. Deviations from an acid medium can occur due to the taking of medication, diet and/or health status. Deviations from the ideal state (pH value between 1.5 and 2) lead to a massive adulteration of the measurement result, such that the measured pH value allows no conclusion of the ammonia concentration (and therefore of a presence of Helicobacter pylori).